High Error Rate Found In Lyme Disease Testing

September 22, 1992|The Washington Post

Current blood testing for the diagnosis of Lyme disease is of "questionable value," according to a new study that documents how often laboratories conducting the tests make mistakes. University of Wisconsin researchers found that the accuracy and reliability of the tests varied widely, not only between laboratories but also within the same one.

Lori L. Bakken and colleagues sent blood samples from individuals known to have Lyme disease, as well as samples from those with no history of the illness, to 45 laboratories participating in a quality control program through the university-based Wisconsin State Laboratory of Hygiene. As many as 21 percent of the labs failed to identify correctly blood samples with evidence of known high levels of Lyme infection, including patients with late stage or chronic Lyme disease.

The laboratories did even worse on blood samples from a Lyme disease patient with lower levels of Lyme antibody, failing to identify them correctly 55 percent of the time. The University of Wisconsin team also found "a striking inability" of many laboratories to duplicate their own results when a test was repeated. And from 5 to 27 percent of the time, depending on which of two tests was used, the laboratories falsely identified samples as having evidence of Lyme disease infection when there was none.

"Our results indicate there is an urgent need for standardization of current testing methodologies," warned the authors of the study, published in the Aug. 19 Journal of the American Medical Association.

Their study confirms longstanding concerns about the difficulties in diagnosing the disease, which is transmitted to humans by tiny deer ticks infected with a spirochete called Borrelia burgdorferi. Since many victims do not know they have been bitten or may not get the typical red rash, doctors who suspect Lyme often order blood tests in individuals with suspicious flulike symptoms or muscle and joint pains.

The Wisconsin study involved laboratories in Wisconsin, Minnesota, and Illinois and found similar results among hospital laboratories, independent facilities and those in physicians' offices. It found no commercial Lyme disease test kit to be superior, and blamed not only the kits but poor quality control in the laboratories.

Ronald F. Schell, who co-authored the study, said study results were representative of problems found in laboratories around the country.